Cornea is a transparent avascular tissue having a diameter of about 1 cm and a thickness of about 1 mm, while conjunctiva is a mucosal membrane covering the eyeball surface posterior to the corneal margin, and the back face of the eyelid. The cornea and the conjunctiva are known to significantly affect the visual function. Keratoconjunctival disorders caused due to a variety of diseases such as corneal ulcer, keratitis, conjunctivitis, dry eyes and the like may adversely affect normal architecture of epithelium, and furthermore, may impair structures and functions of the stroma and endothelium, when the repair of these disorders are retarded, alternatively when these disorders are prolonged without making repair on some grounds. That is because the cornea and the conjunctiva are connected tissues. In these years, with the development of cell biology, factors participating in cell proliferation, migration, adhesion, extension, differentiation and the like had been elucidated, and it was reported that these factors play important roles in repair of corneal disorders (Japanese Review of Clinical Ophthalmology, 46, 738-743 (1992), Ophthalmic Surgery, 5, 719-727 (1992)).
Japanese Patent No. 2976885 discloses that 5-[4-(6-methoxy-1-methyl-1H-benzimidazol-2-ylmethoxy)benzyl]thiazolidine-2,4-dione is effective as a therapeutic agent for diseases resulting from insulin resistance such as diabetes and hyperglycemia, and for inflammatory diseases such as osteoarthritis and rheumatic arthritis, while JP-A Nos. 2001-39976 and 2002-220336 disclose that the hydrochloride of the aforementioned compound exhibits excellent oral absorptivity, as a result of remarkable elevation of solubility in comparison with the free form thereof (the compound without forming a salt).
However, no report has been found in which pharmacological actions of the aforementioned compound on ophthalmic diseases such as keratoconjunctival disorders were studied.